The present invention relates to a method of reducing the astringency of dentifrice composition containing stannous. The present inventor has discovered that the use of a poloxamer will reduce the astringency, bitterness, and sourness that is associated with stannous. It has also been discovered that certain polyphosphates, in particular, linear polyphosphates with average chain lengths of about 4 or more will also help to reduce the astringency of the stannous. This reduction in astringency occurs without reducing the efficacy of the stannous from either the poloxamer or the polyphosphate.
The term "stannous" as used herein, is defined to mean the stannous that is in a dentifrice. It may refer to the stannous ions that are provided by a stannous salt. Stannous salts which contain stannous ions are commonly known. Stannous has been found to provide antigingivitis and antiplaque benefits. In addition, stannous may also help to improve breath and reduce sensitivity. Dentifrices containing stannous are also known to cause staining on a subject's tooth surface as well as having an astringent feel. The astringency is most noticeable after use of the product. U.S. Pat. No. 5,780,015 describes the use of an oxyethylated reaction product of hydrogenated castor oil to help reduce astringency. To improve consumer acceptance of dentifrice composition containing stannous, additional dentifrice compositions containing the benefits of stannous but without the astringency are needed.
It is an object of the present invention to provide a method of reducing the astringency of dentifrice composition containing stannous by administering to a subject dentifrice composition comprising stannous. The dentifrice composition comprises stannous ions, poloxamer, and aqueous carriers. The efficacy of this dentifrice composition containing stannous will not be reduced by the poloxamer. The dentifrice composition may also contain a polyphosphate as long as the dentifrice has a low water content and does not contain stannous fluoride as the source of stannous ions. The polyphosphate will also not reduce the efficacy of the stannous. Alternatively, the dentifrice composition may be a dual phase composition. The first dentifrice composition will contain a polyphosphate having an average chain length of about 4 or more and have a low water content and the second dentifrice composition will contain stannous ions. The poloxamer will be present in the first or second dentifrice compositions or both compositions.
These and other objects of the present invention will become readily apparent from the detailed description which follows.
All percentages used herein are by weight of the specific dentifrice composition, unless otherwise specified. The ratios used herein are molar ratios of the overall composition, unless otherwise specified. All measurements are made at 25.degree. C., unless otherwise specified.